It may look innocent, but a simple WhatsApp message containing a small black dot emoji can be used to crash your app or smartphone in seconds.

Inside the Reddit community for the Facebook-owned chat service, users have complained for days about the glitch—known as a "text bomb"—which stores thousands of hidden characters that will overwhelm the app if clicked. The text in circulation shows the emoji and a short message reading: "Touch here."

While invisible on the screen, the text bomb stores approximately 6,000 Unicode characters that are used to dictate how letters display in order of left-to-right or right-to-left. Multiple computer experts who analyzed the backend code suggest WhatsApp is currently unable to process changes of text direction at scale.

It is believed that the booby-trapped texts mostly impact devices on Google's Android OS. WhatsApp and Google did not respond to a request for comment.

The WhatsApp logo is seen on a smartphone.REUTERS/Dado Ruvic/Illustration

Tom Scott, computer coder and popular tech YouTuber, said in a video that Android developers would likely release a fix within the next two weeks. The black dot could be substituted for any other emoji and still work, he added. "The black spot itself almost certainly isn't the cause of your phone's doom," Scott explained.

A separate crash text—which again surfaced on a Reddit thread—was recently designed to read: "This is very interesting!" alongside a smiley-face emoji.

The alleged developer of the attack, who uses Instagram under the name Jens Hindersmann, wrote: "Sometimes not only WhatsApp is crashing, my whole system process got stuck, and I was forced to restart my phone. Use it carefully."

In an update to the thread, the coder added: "I discovered this glitch! Be careful, these text messages can crash WhatsApp, Reddit, Instagram and/or the whole smartphone." He commented: "Funny little thing to play with."

A YouTube video uploaded on May 4 showed the bug in action. In each case, the emoji plays no role—it is the hidden mass of characters to blame for the issue.

Text bombs have existed in various forms for years. Earlier this year, it was confirmed that Apple devices could be stalled with the use of a single letter from Telugu, an Indian language. Security experts stress that the crashing is unlikely to cause lasting faults to a smartphone and are typically described as a nuisance.